Blade electrode assembly



Apnl 5, 1966 T. R. PEZZACK BLADE ELECTRODE ASSEMBLY Filed Nov. 29, 1961 INVENTOR. THOMAS R. PEZZACK A 7'7'ORNEY United States Patent 3,244,611 BLADE ELECTRODE ASSEMBLY Thomas R. Pezzaclr, Toronto, Ontario, Canada, assignor to Union Carbide Canada Limited, a corporation of Canada Filed Nov. 29, 1%1, Ser. No. 155,550 4 Claims. (Cl. 264-289) This invention relates to electrolytic cells, such as the Hooker cell, and more particularly, it relates to an improved blade electrode assembly for such cells.

In an electrolytic cell of the Hooker type which is used for the production of chlorine by the electrolysis oi chlorine yielding aqueous solutions such as brine, a plurality of alternate rows of oil impregnated graphite anodes and semi-permeable diaphragm-covered perforated cathodes, are submerged in an electrolyte. The anodes are vertically positioned and cast in lead at the bottom of the cell, and receive electrical energy from a plurality of bus bars which are embedded in the lead base of the cell. During the operation of such cell, the electrolytic action causes the anodes to be consumed leaving a residue of stubs in the lead. Due to this fact that the anodes are cast in lead, considerable cell productive time is lost and con siderable labor is required in order to remove the anode stubs from the lead and replace them with new anodes. In addition the lead must be purified for reuse. Another disadvantage of the conventional construction is the nuisance created by the obnoxious fumes evolved when the oil impregnated anodes are immersed in the molten lead. These fumes preclude visual observation and thus complicate the work of personnel who are repairing and overhauling the cell.

One means for eliminating the disadvantages of this type construction is disclosed in United States Patent No. 2,967,142 granted January 3, 1961 to John P. Oliver. According to that invention, there is provided an electrode assembly for an electrolytic cell in which a plurality of carbon or graphite anodes are detachably fitted to a carbon or graphite header. The header is cast in lead at the bottom of the cell and the plurality of anodes are joined to the header in a spring fit relation. The anodes extend vertically upward in the cell and may be readily assembled and disassembled from the header. The bus bars are cast in the lead at the bottom of the cell and the electrical current or energy supplied to the bus bars must travel through the lead and header prior to reaching the anodes. The difficulties encountered with this type of construction have been in replacing the header itself, and in the relatively high electrical resistance that must be overcome between the bus bars and anodes.

It is therefore the principal object of this invention to provide an improved method of supplying electrical energy to the anodes of an electrolytic cell, of which the Hooker cell is an example.

Another object of this invention is to increase the efilciency of such cells.

Yet another object is to minimize the non-productive time caused by header and anode replacements and general overhaul of an electrolytic cell of the Hooker and like type cells.

The objects of the invention are accomplished by eliminating the need for lead in an electrolytic cell by incorporating both the anodes and the bus bars in a carbonaceous plate. The plate is provided with parallel series of slots or grooves for positioning a multiplicity of anodes in each groove. The plate is also provided with a plurality of blind cavities therein, in which are positioned the bus bars and they are secured and connected to the plate by a tamped copper composition such as copper powder or copper amalgam.

In order that the invention may be more clearly under- 3,244,115 Patented Apr. 5, 1966 stood, reference is made to the drawing in which there is shown a blade electrode assembly as may be used in the Hooker cell and in which:

FIG. 1 is a partial vertical section of a Hooker type chlorine cell which embodies the principles of the invention; and

FIG. 2 is a fragmentary detail of the structure of FIG. 1 prior to assembly, and enlarged for clarity; and

FIG. 3 is a partial sectional view of a modification of the structure of FIG. 1.

Referring now to the drawing and particularly to FIG. 1, there is shown in upper header plate 10 and a lower header plate 11, both made of a carbonaceous material and impregnated with oil or resin. The upper header plate 10 is provided with a plurality of slots or grooves 12 on its upper surface 13 in which anodes 14 are positioned and secured. The upper surface 13 of the upper header plate 10 is coated with an insulating membrane or inert non-conductive coating 15 between the parallel rows of anodes 14.

In FIG. 2 is shown an anode 14 prior to being assembled to the upper header plate 16. In this embodiment, the anode 14 is machined or otherwise shaped to form a tongue 16 having a slot or kerf 17 along its length to form an easily detachable spring fit joint with the grooves 12 of the upper header plate 10. At least one cavity 18 is provided in the base of the upper header plate 10 and this cavity 18 is shaped to accommodate a bus bar 19 preferably made of copper. The bus bar 19 may be rectangular or any other suitable shape and may be solid or hollow, or may even be a flexible cable if desired.

The lower header plate 11 is suitably cemented to the upper header plate 10 thereby forming the whole shape of the cavity 18 in order to accommodate the rectangular copper bus bar 19. It will be appreciated that of course the plates 10 and 11 could be combined as one member having blind cavities therein for the bus bars. The bus bars 19 are secured and connected to the header plates 10 and 11 by a copper composition 20 such as copper powder or copper amalgam which has been driven in and down the cavity 18 by tamping. This method of securing and connecting the bus bars 19 by tamping a copper composition 20 in the cavities 18 insures good intimate contact with the header plates 10 and 11 and has low contact resistance which stabilizes after the first 500 hours of operation and results in very little power loss through the header plates 10 and 11. Electric current is supplied to the copper bus bars 19 by an external source (not shown).

The copper powder is preferably of the nodular type and the copper amalgam has a preferred range of proportion, namely about 61% copper powder and 39% mercury. The preferred copper composition is copper powder since it has better voltage stability and a lower long term voltage drop across the connection than copper amalgam even though it does have a slightly higher initial voltage drop than the amalgam. In addition the copper powder is somewhat more economical than copper amalgam due to the high cost of mercury.

In FIG. 3 a modified anode 21 is shown which terminates in a tongue 22. The tongue 22 is slightly wider in the disassembled condition than the grooves 23 of the header plate 24. This provides a force-fit type of connecting relationship which is referred to in the art as an interference fit whereas the connecting relationship of FIGS. 1 and 2 depict a spring-fit relation.

Important advantages which accrue from the construction of the invention, namely, in using header plates of carbonaceous composition, having anodes securely held and positioned by a plurality of grooves therein, and which are supplied electrical current from copper bus bars which are embedded in and connected to the plate by a tampecl copper composition, are as follows: The non-productive time lost due to the overhauling is minimized because the plate and anodes are readily replaceable since netither is cast in lead in the fabrication of the cell, lower cell voltages and Operating temperature are realized, and higher overall cell efiiciency is achieved.

What is claimed is:

1. A blade electrode assembly for an electrolytic cell, said blade electrode assembly comprising at least one carbonaceous plate having parallel uniformly spaced slots therein, an anode engaged in each slot, said plate also having therein at least one cavity in which a bus bar is embedded and secured thereto by a tamped copper amalgam.

2. The blade electrode assembly of claim 1 wherein said amalgam comprises about 61% copper and 39% mercury.

3. A blade electrode assembly for an electrolytic cell of the Hooker type, said blade electrode assembly cornprising at least one carbonaceous plate having parallel uniformly spaced slots therein, an anode engaged in each slot by a spring fit relation, said plate also having therein at least one cavity in which a copper bus bar is embedded and secured thereto by tamped copper amalgam.

4. A blade electrode assembly for an electrolytic cell of the Hooker type which is used for the production of chlorine by the electrolysis of brine, said blade electrode assembly comprising at least one cell header plate of graphite having parallel uniformly spaced slots therein, a graphite anode engaged in each slot by a spring fit relation, said cell base plate also having therein a plurality of cavities inwhich copper bus bars are embedded and secured thereto by tamped copper amalgam comprising about 61% copper and 39% mercury.

References Cited by the Examiner UNITED STATES PATENTS r 667,421 2/1901 Blackman 204286 1,863,429 6/1932 Willmore 339278 2,655,641 10/1953 Asatf 339-278 2,967,142 1/1961 Oliver 204--266 FOREIGN PATENTS 215,166 5/1961 Austria.

19,368 of 1902 Great Britain;

JQHN H. MACK, Primary Examiner.

D. R. JORDAN, Assistant Examiner. 

1. A BLADE ELECTRODE ASSEMBLY FOR AN ELECTROLYTIC CELL, SAID BLADE ELECTRODE ASSEMBLY COMPRISING AT LEAST ONE CARBONACEOUS PLATE HAVING PARALLEL UNIFORMLY SPACED SLOTS THEREIN, AN ANODE ENGAGED IN EACH SLOT, SAID PLATE ALSO HAVING THEREIN AT LEAST ONE CAVITY IN WHICH A BUS BAR IS EMBEDDED AND SECURED THERETO BY A TAMPED COPPER AMALGAM. 